Electrical control system



Dec. 29, 1936. J. w. WATTLES. 3D v I 2,065,844

ELECTRICAL. CONTROL SYSTEM Filed April 28, 1933 Patented Dec. 29, 1936 PATENT vOFFICE y ELECTRICAL CONTROL SYSTEM Joseph Warren Wattles, 3d, Canton, Mass., as-

signor to Minneapolis-Honeywell Regulator'- Company, Minneapolis, Minn., a corporation of Delaware Application April 28, 1933, Serial No. 668,353

i3 Claims.

This invention relates to electrical temperature control systems for buildings and more particuiarly to systems for controlling an operating device, such as a heat regulator, in response to one or more controllers such as clock switches, thermostats, relays, etc., the principal objects of the invention being to improve the accuracy and reliability of such controls, to render the system more responsive to varying conditions of operation, and generally to improve the construction and operation of systems of the character referred to.

For the purpose of illustrating the genus of the invention a typical concrete embodiment is shown in the accompanying drawing in which;

Fig. 1 is a schematic Wiring diagram showing a portion of the associated structure in cross-section; and

Fig. 2 is an elevational view, with parts in cross-section, of a typical application of the system.

. 'I'he particular embodiment of the invention chosen for the purpose of illustration comprises a casing B containing two thermostats 40 and I0 and a resistance heater I and a casing C containing various control elements therein. The thermostat 40 is connected to one side 2 of a source of current by means of a conductor 3, and the thermostat 1l) is connected to the same side 2 of a source of current by means of apconductor 4, a time switch 2| contained therein, and a. conductor I3. 'Ihe contacts of the thermostats 40 and 'l0 are connected together through a conductor 5 which is connected to the other side 6 of the source of current through a common return having two branches. One of the branches comprises the resistance heater I, conductor 1, rheostat 8, and conductor 9; the other branch comprises a conductor IIJ, two-way switch I I, one-way switch I2, relay winding I3, conductor I4, and

conductor 9. The relay coil I3 has a pilot light I5 connected in parallel therewith to indicate when the relay winding is energized. The switch II is a manually operated two-way switch for connecting the relay I3 either to the aforesaid conductor I0 or to a conductor I6 connected to the conductor 3. The relay I3 is provided with an armature II which, when the relay is energized, closes a circuit from one side 2 of a source of current through conductors I8 and I9, armature I1, conductors 20 and 24 connected to an operating device 25, conductors I4 and 9 to the other side 6 of the source of current. The switch 2l contained in the conductor 4 is controlled by a clock which is driven by the motor 22 connected across the source terminals 2 and 6.

In the typical installation shown in Fig. 2 the box B is located on top of the building 23 to be heated and the parts contained within the broken line rectangle C of Fig. l are located in the basement of the building, the conductors 20 and 24 leading to an electromagnetically controlled steam valve 25 which is connected in the steam line 26 for supplying heat to the various rooms of the building 23 and the box B simulating the building in heat dissipating characteristics.

The box or casing B comprises a top 21, a bottom 28 and four side Walls 29, these parts being suitably interconnected in snugly intertting' relationship and being covered with a layer 30 of sheet copper or the like. In addition to the covering 39 the casing is provided with a cover 3|` which is mounted in spaced relation to the casing v by means of screws 32. The sides 29 of the casing are provided with ventilators in the form of screws 33 having very small axial bores, the degree of ventilation being adjustable by interchanging screws having different size bores. The box is also provided with interior loading means in the form of bodies 34 of metal to retard the rate of heating and cooling of the box, the loading means being adjustable by substitution of bodies having different sizes and/or different conductivity.

In operation the steam valve 25 is opened to supply heat to the building when the relay I3 is energized and, when the relay is deenergized, the steam valve closes to shut off the heat. To energize the relay I3 the switch I2 is closed and the switch II is moved to one of its two limiting positions, to the left for automatic operation and to the right for manual control. When the switch II is in the left-hand position the relay I3 is connected to the two thermostats in parallel, to the thermostat 40 through circuits I3-I2--I I I054|l3269|4 and to the thermostat 'I0 through the circuits I3-I2-I I-I0-5 10-4-2I-I8--2-B-9-1'I4. Thus the relay I3 is energized when either ofthe two thermostats is in closed position, assuming the clock switch 2| to be closed. The thermostat 40 is set to open at a relatively low temperature (for example, 40 F.) and the thermostat 10 is set to open at a relatively high temperature (for example, 70 F.). Consequently when the clock switch 2l is closed the relay I3 is not deenergized until both thermostats open, that is until the temperature in the casing B rises to 70. When the clock switch 2| is open the high temperature thermostat 'I0 is rendered inoperative and the relay therefor is deenergized when the low temperature thermostat 40 opens.

From the foregoing description it will be evident that the circuit IIJ- I II2I3I4 constitutes a common return for the two thermostats 40 and 10; and it will also be evident that the circuit I-'l-8-9 of the auxiliary heater I also constitutes a common return for the two thermostat circuits 3 and 4. Thus the heater I is energized in parallel with the relay I3 when either of the thermostats is closed.

To operate the relay I3 manually, the switch II is moved to the right-hand position whereupon the circuit of the relay I3 is closed through 2-3-I6-I I-IZ-I3-I4-S-B, the relay I3 remaining energized until the switch II is moved from the right-hand position. During this manual operation the heater I is energized, so long as either thermostat is closed, over the circuit 2-3-40-5-I-'I-8-9-6 through thermostat 40 and over the circuit 2-I8-2 I-II-IU,-5-I

1--8-9-6 through thermostat 10. Thus the.,

casing is kept at a temperature of at least approximately 40 (and approximately 70 during the daytime) so that when the switch II is again moved to the left for automatic operation the casing is already at a temperature of atleast 40, whereby the relay I3 will not remain energized for an excessive period of time while the casing B is being warmed up as would be the case if heat were wholly discontinued from the casing B during a prolonged period of manual operaof the box B by the heater I may be regulated to correspond with the heat requirements of the building from the location in the building where the switches and relays are operated.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

1. An electrical control system comprising a respectively, said circuits having a common re turn and said heater being connected in said common return.

2. An electrical control system comprising a device for controlling the supply of heat to-a building, two thermostats for controlling the device, one thermostat functioning at a relatively low temperature and the other at a relatively high temperature, said thermostats being located outside said building in casing means which simulates said building in radiation characteristics and which is subjected to similar conditions of wind and sunshine, auxiliary heating means associated with each thermostat in said casing means, circuit connections interconnecting each thermostat with its associated heating means and with said device, whereby heat is supplied to the thermostat while heat is supplied to said building, and means in the building for disconnecting the high temperature thermostat when the temperature in the building is to be reduced.

3. An electrical control system comprising a device for controlling the supply of heat to a building, two thermostats for controlling the device, one thermostat functioning at a relatively low temperature and the other at a relatively high temperature, said thermostats being located outside said building in casing means which simulates said building in radiation characteristics and which is subjected to similar conditions of wind and sunshine, the casing means having a restricted opening for ventilation in proportion to that of the building, auxiliary heating means associated with each thermostat in said casing means, circuit connections interconnecting each thermostat with its associated heating means and with said device, whereby heat is supplied to the thermostat while heat is supplied to said building, and means in the building for disconnecting the high temperatur-e thermostat when the temperature in the building is to be reduced.

4. An electrical control system comprising a device for controlling the supply of heat to a building, a thermostat for controlling the device, said thermostat being located outside the building in casing means which simulates said building in radiation characteristics and which is subjected to similar conditions of wind and temperature, the casing means having restricted openings on opposite sides for ventilation in proportion to that of the building, auxiliary heating means associated with said thermostat in said casing means and having sufcient capacity to raise the temperature ofthe casing means to a. predetermined value under all normal outdoor conditions, and circuit connections interconnecting said thermostat with said device and heating means, whereby heat is supplied to the thermostat whileV heat is supplied to said building.

5. An electrical control system comprising a device for controlling the supply of heat to a building, a thermostat for controlling the device.

said thermostat being located outside the build` ing in casing means which simulates said building in radiation characteristics and which is subjected to similar conditions of wind and temperature, the casing means having a restricted opening for ventilation in proportion to that of the building, auxiliary heating means associated with said thermostat in said casing means and having surlicient capacity to raise the temperature of the casing means to apredetermined value under all normal outdoor conditions, and circuit connections interconnecting said thermo-l l stat with said device and heating means, whereing in radiation characteristics and which is subjected to similar conditions of Wind and temperature, the, casing means having restricted openings on opposite sides for ventilation in proportion to that of the building, auxiliary heating means associated With said thermostat in said casing means and having suicient capacity to raise the temperature of the casing means to a predetermined value under all normal outdoor conditions, circuit connections interconnecting said thermostat with said device and heating means, whereby heat is supplied to the thermostat while heat is supplied to said building, and means in said building for regulating the rate of heat supply by said auxiliary heating means to said casing means.

7. An electrical control system comprising a device for controlling the supply of heat to a building, a thermostat for controlling the device, said thermostat being located outside the building in casing means which simulates said building in radiation characteristics and which is subjected to similar conditions of Wind and temperature, the casing means having a restricted opening for ventilation in proportion to that of the building, auxiliary heating means associated With said thermostat in said casing means and having sufiicient capacity to raise the temperature of the casing means to a predetermined value under all normal outdoor conditions, and circuit connections interconnecting said thermostat with said device and heating means, Whereby heat is supplied to the thermostat while heat is supplied to said building, loading means for automatically delaying the operation of said thermostat when heat is turned on after a prolonged period of cold, and means in said building for regulating the rate of heat supply by said auxiliary heating means to said casing means.

8. In a heating system for a building, the combination of heating means for the building, a control housing having a Ventilating opening therein, heating means for the control housing, thermostatic means responsive to the temperature Within the control housing for controlling both heating means, the heating means being so proportioned that the heat inputs to the building and to the control housing are proportional to the heat loss characteristics of the building and the control housing, and means for reducing the effective area of the opening in the control housing to adjust the heat loss characteristics thereof. v

9. In a heating system for a building, the combination of heating means for the building, a control housing subject to the sameatmospheric conditions as the building, and provided with a Ventilating opening, means for reducing the effective area of the opening in the control housing to determinethe heat loss characteristics thereof, heating means for the control housing and of sufficient capacity to raise the temperature of the control housing to a predetermined Value during cold weather, and means responsive to the temperature Within the control housing for controlling both heating means to cause the heat inputs to the building and the control housing to be proportional to the heat losses from the building and the control housing.

10. An electrical control system comprising a device for controlling a supply of heat to a building, a casing outside the building, said casing having radiation characteristics similar to that of the building and being subjected to conditions of wind and sunshine, similar to that of the building, said casing containing two thermostats and a heater, one thermostat functioning at a relatively low temperature and the other 'at a relatively high temperature, and circuit connections for concomitantly energizing said heater and said heat supply controlling device in response to either thermostat, and a clock switch for periodically disconnecting the high temperature thermostat.

1l. In a system of the class described, a building to be heated, a control housing capable of storing heat and located outside of said building and subjected to atmospheric conditions similar to that of the building, heating means for said building, heating means for said control housing, the heat supplied by said building heating means and said control housing heating means being proportional to the heat losses of said building and said control housing, two thermostats responsive to temperature changes in said control housing, one thermostat functioning at a relatively low temperature and the other at a relatively high temperature, and means controlled by said thermostats for concomitantly energizing both of said heating means in response to either thermostat.

l2. In a system of the class described, a building to be heated, a control housing of substantial mass outside of said building subjected to atmospheric conditions similar to that of the building, heating means for said building, heating means for said control housing, the heat supplied by said heating means to the building and the control housing being proportional to the heat losses of said building and said control housing,

two thermostats responsive to temperature changes in said control housing, one thermostat functioning at a relatively low temperature and the other at a relatively high temperature, two

circuits connecting said building heating means with said thermostats respectively, said circuits having a common return and said control housing heating means being connected in said common return.

13. In a system of the class described, a buildi ing to be heated, a control housing adapted to store heat and located outside of said building and subjected to atmospheric conditionssimilar to that of the building, heating means for said building, heating means for said control housing,

the heat supplied by said building heating means and said control housing heating means being proportional to the heat losses of said building and said control housing, two thermostats responsive to temperature changes in said control housing, one thermostat functioning at a relatively low temperature and the other at a relatively high tempcrature, circuit connections for concomitantly energizing both of said heating means in response to either thermostat, and a clock switch for periodically disconnecting the high temperature thermostat.

JOSEPH WARREN WA'I'I'LES, 3RD. 

